Floribunda rose plant named ‘GRAaus’

ABSTRACT

‘GRAaus’ is a new and distinct floribunda type  Rosa  hybrid cultivar which is characterized by the combination of an upright to semi-weeping growth habit, excellent resistance to  Diplocarpon rosae , nearly continuous flowering, white double-type flowers with tinges of pale pink as flowers age, a moderate rose fragrance, and the stability of these characteristics from generation to generation. The new cultivar is generally suited to landscape applications.

Latin name of genus and species: The Latin name of the genus and species of the novel variety disclosed herein is Rosa hybrid.

Variety denomination: The inventive variety of Rosa hybrid disclosed herein has been given the variety denomination ‘GRAaus’.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to the Australian Plant Breeder's Rights application number 2015/087, filed on Apr. 27, 2015, which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct Rosa hybrid, floribunda rose cultivar, which has been given the variety denomination of ‘GRAaus’.

Parentage: ‘GRAaus’ is a seedling selection which resulted from the controlled cross-pollination of an unnamed Rosa hybrid female breeding line and an unnamed Rosa hybrid male breeding line. Both parents, developed by the same inventor and never commercially released, exhibited traits deemed commercially significant and desirable.

After many years of trialing, the female parent was confirmed to possess a combination of desirable traits such as complete resistance to rose black spot disease, complete resistance to powdery mildew, and flowers with a strong citrus-like perfume borne on a bushy plant growing to 1.2 m tall and wide. The male parent was selected for use in breeding after trialing confirmed the presence of strong true-rose perfume and a bright, modern flower color. During the summer of 2010, the female parent was emasculated and was manually pollinated with pollen from the male parent. In autumn of 2010, seed was collected from hips produced by the female parent and a number of seedlings were grown to a mature size, including the claimed plant. These progeny were further evaluated for desirable traits such as black spot disease resistance and strong perfume, and in June of 2011 the claimed plant was first observed. In January of 2013, after further evaluation for desirable traits, the claimed plant was deemed to be garden-worthy and suited to widespread cultivation. It was given the denomination, ‘GRAaus’.

Asexual Reproduction: Asexual propagation of ‘GRAaus’, by way of softwood stem cuttings, was first performed in May of 2011 at the inventor's nursery in Highfields, Australia. Through more than twelve subsequent generations, the unique features of this cultivar have proven to be stable and true to type.

SUMMARY OF THE INVENTION

The following characteristics have been repeatedly observed and represent the distinguishing characteristics of the new Rosa cultivar ‘GRAaus’. These traits, in combination, distinguish ‘GRAaus’ as a new and distinct cultivar.

-   -   1. Rosa hybrid ‘GRAaus’ exhibits an upright to semi-weeping         growth habit; and     -   2. Rosa hybrid ‘GRAaus’ exhibits excellent resistance to the         plant pathogen, Diplocarpon rosae, commonly referred to as rose         black spot disease; and     -   3. Rosa hybrid ‘GRAaus’ exhibits nearly continuous flowering;         and     -   4. Rosa hybrid ‘GRAaus’ exhibits a double flower type; and     -   5. Rosa hybrid ‘GRAaus’ exhibits white colored flowers with pale         pink intonations as flowers fade; and     -   6. Rosa hybrid ‘GRAaus’ exhibits flowers with a moderate rose         fragrance.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates, as nearly true as it is reasonably possible to make the same in color photographs of this type, an exemplary 15 month old ‘GRAaus’ plant grown outdoors at the inventor's commercial nursery in Highfields, Australia.

FIG. 2 illustrates, as nearly true as it is reasonably possible to make the same in color photographs of this type, the typical foliage and flower of ‘GRAaus’.

DETAILED BOTANICAL DESCRIPTION

The following observations and measurements, made in February of 2016, describe averages of two own-root specimens of one year old ‘GRAaus’ plants. The plants were grown outdoors in 20 cm containers, in a soilless pine bark based growing media, at the inventor's nursery in Highfields, Australia. No shade or supplemental light was provided. Temperatures ranged from approximately 17 to 35 degrees Celsius during the day and 7 to 18 degrees Celsius at night. Standard practices for irrigation, fertilizer and pest control were applied at appropriate times during the growing season. The plants were pruned three times during the growing season using accepted techniques for rose pruning.

Those skilled in the art will appreciate that certain characteristics will vary with older or, conversely, with younger plants. ‘GRAaus’ has not been observed under all possible environmental conditions. Where dimensions, sizes, colors and other characteristics are given, it is to be understood that such characteristics are approximations or averages set forth as accurately as practicable. The phenotype of the variety may differ from the descriptions set forth herein with variations in environmental, climatic and cultural conditions. Color notations are based on The Royal Horticultural Society Colour Chart, The Royal Horticultural Society, London, 2007 Fifth Edition except where common terms of color are used.

A botanical description of ‘GRAaus’ and comparisons with the parents and the most similar commercial cultivar of Rosa hybrid are provided below.

-   General plant description:     -   -   Growth habit.—Upright to semi-weeping.         -   Growth rate.—Approximately 1 year to reach 40 cm.         -   Dimensions.—40 cm tall and 40 cm wide.         -   Environmental tolerance.—Very good heat tolerance; cold             hardiness is unknown.         -   Disease resistance.—Excellent resistance to powdery mildew             (Sphaerotheca pannosa) and blackspot (Diplocarpon rosae).         -   Propagation.—Technique — Softwood stem cuttings. Time to             initiate roots — About 13 days at approximately 21 degrees             Celsius at root zone and 18 degrees Celsius ambient             temperature. Time to produce a rooted cutting — About 25             days at approximately 21 degrees Celsius at root zone and 18             degrees Celsius ambient temperature. -   Root system: White fibrous roots with many root hairs extending from     lesser roots in a featherlike arrangement. -   Branches:     -   -   Branching habit.—Irregular branching from mature branches,             breaking first from the uppermost buds near the apex of each             shoot.         -   Quantity.—Numerous.         -   General dimensions.—Approximately 30 cm long; 0.6 cm in             diameter near the base and tapering to 0.3 cm.         -   Immature branches.—Diameter — Approximately 0.3 cm. Texture             and pubescence — Smooth; glabrous to moderately pubescent.             Color — Near RHS 136D. Prickles — Density — Moderate. Color             — Near RHS 177A. Shape — Concave. Texture — Smooth.         -   Mature branches.—Diameter — Approximately 0.7 cm, after one             year. Texture and pubescence — Smooth and glabrous. Color —             Near RHS 135D. Prickles — Density — Moderate. Color — Near             RHS 177A. Shape — Concave. Texture — Smooth. -   Leaves:     -   -   Arrangement.—Alternate imparipinnate compound leaves.         -   Quantity.—Approximately 7 per mature branch.         -   Attachment.—Petiolate.         -   Leaf internode length.—1.7 cm.         -   Dimensions.—Approximately 6 to 6.5 cm long and 5 cm wide.         -   Petiole.—Dimensions — Average of 0.5 to 1.0 cm long and 0.1             to 0.2 cm wide. Color — RHS 142C. Texture and pubescence —             Smooth and glabrous. Prickles — Not present. Stipitate             glands — Not present.         -   Stipule.—Dimensions — 0.7 cm long and 0.2 cm wide. Color —             near RHS 144A. Texture and pubescence — Smooth and glabrous.             Margins — Ciliate. Apex — Apiculate. Base — Winged. Prickles             — Not present. Stipitate glands — Not present.         -   Rachis.—Dimensions — 1.0 cm long and 0.1 cm wide. Color —             Near RHS 144A. Prickles — Not present. Stipitate glands —             Not present.         -   Leaflets.—Quantity — Normally 5 leaflets on axillary leaves.             Dimensions — Average size of the terminal leaflet is 3.5 cm             long and 2.5 cm wide. Shape — Ovate. Apex — Acuminate. Base             — Ovate. Margins — Serrated. Texture, pubescence and luster,             adaxial surface — Smooth, glabrous, and semi-glossy.             Texture, pubescence and luster, abaxial surface — Smooth,             glabrous, and matte. Juvenile foliage color, adaxial surface             — Near RHS 142B, with some anthocyanin intonations, RHS 53A,             at the margins and midrib. Juvenile foliage color, abaxial             surface — Near RHS 145C, with some anthocyanin intonations,             RHS 53A. Mature foliage color, adaxial surface — Near RHS             N138B. Mature foliage color, abaxial surface — Near RHS             138D. Venation — Pinnate. Venation color, adaxial surface —             Near RHS N138B. Venation color, abaxial surface — Near RHS             138D. Petiolule — Dimensions — 0.2 cm long and 0.1 cm wide.             Color — Near RHS 144A. Prickles — Not present. Texture —             Smooth. -   Inflorescence:     -   -   Inflorescence type.—Terminal corymb consisting of             approximately 2 to 4 pedicellate flowers.         -   Blooming habit.—Almost continuous from October through June             in the southern hemisphere.         -   Time to flower.—6 to 8 weeks for a new stem to mature and             flowering begins to occur once a stem matures.         -   Dimensions.—10 cm from the base of the lowest pedicel to the             farthest distal flower and the width from farthest             outstretched flower on one side of the inflorescence to the             farthest outstretched flower on the opposite side is 15 cm.         -   Peduncle.—Dimensions — 3.5 cm long and 0.2 cm in diameter.             Color — Near RHS 144B. Strength — Strong. Texture and             pubescence — Smooth and glabrous. Prickles — Not present. -   Bud:     -   -   Shape.—Ovate.         -   Size.—2 cm long and 1 cm in diameter.         -   Color.—Near RHS 145B. -   Flower:     -   -   Pedicel.—Dimensions — 3.5 cm long and 0.3 cm wide. Color —             Near RHS 144B. Strength — Strong. Texture — Smooth.         -   Calyx.—General — Comprised of five polysepalous sepals, with             strong foliaceous appendages present on all sepals. Diameter             of calyx — 0.5 cm. Sepals — Color, interior surface — RHS             145D. Color, exterior surface — RHS 145B. Dimensions — 2.0             cm long and 0.6 cm wide. Apex — Acuminate. Base — Flat at             union with receptacle. Quantity — Five. Pubescence — Densely             puberulent. Margins — Two to three strong foliaceous             appendages. Stipitate glands — Not present.         -   Corolla.—General shape of corolla — Cupped and well-rounded             at anthesis; aging to a loose whorl. Rate of opening — 6             days from bud to anthesis. Dimensions — 6 cm in diameter and             3.5 cm deep. Upper profile — Cupped. Lower profile — Flat.             Fragrance — Moderate rose scent. Lastingness — On the plant             for 5 days after anthesis. Persistence — Self-cleaning.             Petals — Petal count — Exhibits double flowers with             approximately 32 petals under normal conditions. Petal             arrangement — Tight whorl, loosening as the flower ages.             Dimensions — 3.2 cm long and 2.2 cm wide. Petal shape —             Obovate. Apex — Rounded to cordate. Base — Flattened, then             obtuse. Petal reflex — Slightly reflexed at apex. Petal             margin — Entire; slightly undulating. Texture — Soft. Aspect             — Slightly ruffled. Petal color, upon opening — Upper             surface — Near RHS NN155D. Lower surface — Near RHS NN155D.             Petal color, at anthesis — Upper surface — Near RHS N155C.             Lower surface — Near RHS N155C. Fading — White, RHS N155C,             with intonations of pale pink, near RHS 27B. -   Reproductive organs:     -   -   Stamens.—Quantity — Approximately 30. Anthers — Shape —             Narrow ovate. Length — 0.1 cm. Color — Near RHS 21B. Pollen             — Many. Pollen Color — Near RHS 3A. Filaments — Color — Near             RHS 8C. Length — Approximately 0.7 cm.         -   Pistils.—Quantity — Approximately 50. Length — Approximately             1.0 cm. Stigma — Shape — Ovate. Color — Near RHS 11B. Styles             — Length — Approximately 0.8 cm long. Color — Near RHS 18C.         -   Ovary.—Dimensions — 0.5 cm long and 0.3 cm wide. Color —             Near RHS 3D.         -   Receptacle.—Shape — Pitcher-shaped. Dimensions — 0.5 cm high             and 0.5 cm wide. Color — RHS 144D. -   Hip and seed:     -   -   Hip.—Shape — Rounded. Dimensions — 1 cm long and 1 cm wide.             Texture — Smooth. Color — Near RHS 138C.         -   Seed.—Shape — Rounded. Dimensions — 1 cm long and 1 cm wide.             Color — Near RHS 134D.

COMPARISONS WITH THE PARENTS

The new rose plant ‘GRAaus’ may be distinguished from its seed parent, an unnamed breeding line, by the following combination of characteristics:

-   -   1. The flowers of ‘GRAaus’ exhibit a distinct white general         tonality, whereas the flowers of the seed parent exhibit a soft         pink general tonality.     -   2. ‘GRAaus’ exhibits an upright to semi-weeping growth habit,         whereas the seed parent exhibits an upright growth habit.

The new rose plant ‘GRAaus’ may be distinguished from its pollen parent, an unnamed breeding line, by the following combination of characteristics:

-   -   1. The flowers of ‘GRAaus’ exhibit a distinct white general         tonality, whereas the flowers of the pollen parent exhibit a         purple general tonality.     -   2. ‘GRAaus’ exhibits an upright to semi-weeping growth habit,         whereas the pollen parent exhibits an upright growth habit.     -   3. ‘GRAaus’ exhibits juvenile foliage colored near RHS 142B with         anthocyanin intonations, whereas the pollen parent exhibits         juvenile foliage colored near RHS 137C with no anthocyanin         intonations.

COMPARISONS WITH THE MOST SIMILAR VARIETY OF COMMON KNOWLEDGE

Plants of the new cultivar ‘GRAaus’ may be distinguished from the commercial variety Rosa hybrid ‘GRAppl’ (U.S. Plant Pat. No. 26,364) by the following combination of characteristics:

-   -   1. The flowers of ‘GRAaus’ exhibit a distinct white general         tonality, whereas the flowers of ‘GRAppl’ exhibit a purple         general tonality.     -   2. ‘GRAaus’ exhibits average leaf dimensions of 6 to 6.5 cm long         and 5.0 cm wide, whereas ‘GRAppl’ exhibits average leaf         dimensions of 13.5 cm long and 8.5 cm wide.     -   3. Mature field-grown ‘GRAaus’ plants exhibit an average plant         height of 75 cm, whereas ‘GRAppl’ exhibits an average plant         height of 120 cm.     -   4. ‘GRAaus’ exhibits a rotund plant shape with more twiggy         stems, whereas ‘GRAppl’ exhibits an upright shape with strong         main stems. 

That which is claimed:
 1. A new and distinct variety of Rosa hybrid plant named ‘GRAaus’, as described and illustrated herein. 